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Britain’s Thermonuclear Bluff

Norman Dombey and Eric Grove

‘Britain Carries Out Second H-Test, Explosion even bigger than the first one,’ the Manchester Guardian reported on Saturday, 1 June 1957. It was the lead news item. The story that followed was datelined ‘Aboard HMS Alert’, Alert being the frigate which housed the representatives of the British press corps invited to see for themselves that Britain, as befitted the third great power in the world, had attained thermonuclear status. According to Reuters, ‘a great multi-coloured fireball above the central Pacific heralded Britain’s second hydrogen bomb test’ off the Malden Islands.

In retrospect, there are two problems with these accounts. First, the test of Orange Herald was held on Friday, 31 May: it would not have been physically possible for the story to appear before the following Monday. In other words, the journalists wrote their stories in advance of the test, on the basis of a briefing from Brigadier Jehu, who had seen the first test – Short Granite – of the 1957 Grapple series on 15 May. Secondly, it now appears very probable that Orange Herald was not an H-bomb at all, but a large A-bomb. Journalists, after all, could not be expected to differentiate between mushroom clouds, and no figures were issued then (or have been since) about the size of the test.

To this day the British Government is very reluctant to give any details about the thermonuclear programme it embarked on 38 years ago: certainly we know more about the early stages of the Soviet thermonuclear programme than we do about the British. However, three things have made it possible for us to attempt a reconstruction of events between 1954 and 1958: an unusually forthcoming obituary, in the Biographical Memoirs of the Fellows of the Royal Society, of Sir William Cook, scientific director of the Grapple test series; some recent disclosures on the part of John Ward, who was employed at the British nuclear weapons laboratory at Aldermaston for six months during 1955; and a group of declassified US documents obtained by Robert Norris of the Natural Resources Defence Council in Washington. It may well be that there are errors in our account – given the habits of secrecy and misinformation which prevail among British governments it could perhaps hardly be otherwise – but what follows is at least an introduction to the issues.

The Orange Herald test was only the most blatant example of Britain’s thermonuclear bluff: it seems that none of the four nuclear tests held in 1957 was a hydrogen bomb test as we now understand it. But the tests had as much to do with public relations, and especially relations with the United States, as with constructing an authentic hydrogen bomb, and the bluff was remarkably successful. Within four years of Churchill’s decision to launch a British H-bomb programme, Britain’s overriding political objective – a special nuclear relationship with the United States – had been achieved. That this goal was reached appears to have been due mainly to the contribution of the physicist John Ward. The closeness of the US-UK special relationship in nuclear weapons which resulted from the combination of this bluff and Ward’s genius has also been a carefully kept secret. In fact, from 1958 onwards the United States transferred to Britain detailed design drawings and material specifications of many of their most modern hydrogen bombs so that Britain could manufacture these US weapons as its own. The story we tell has its ironies: Britain’s initial reason for developing its own H-bombs was that it wanted to be in a position to influence US nuclear policy, but the US ended up with substantial power over British nuclear policy.

There are two basic methods of obtaining usable nuclear energy: fission, or the splitting up of heavy elements into lighter elements, and fusion, where light elements combine to make heavier elements. This defines the distinction between A-bombs and H-bombs: A-bombs are fission bombs where the fuel is uranium-235 or plutonium-239. H-bombs are fusion bombs where the hydrogen isotopes deuterium (hydrogen-2) and tritium (hydrogen-3) form the fuel. The reason these weapons are also called thermonuclear is that temperatures comparable to the temperature of the Sun are needed to initiate the nuclear fusion process. Both the fission and fusion processes liberate substantial amounts of energy, but while the yield of an A-bomb is characteristically measured in kilotons, that of an H-bomb can reach many megatons or millions of tons of high explosive.

Tritium is often added to fission weapons to provide some fast neutrons from thermonuclear processes in order to increase the yield of the weapon. The weapon is still referred to as a fission weapon, however, because almost all the explosive energy comes from fission, not fusion. It is worth bearing in mind that it was exceedingly difficult for the United States to develop megaton hydrogen bombs in which a significant part of the energy came from fusion. Although President Truman had authorised the H-bomb programme in 1950, calculations later that year on one of the world’s first electronic computers showed that the hydrogen bomb design on which the weapons laboratory at Los Alamos had been working since the mid-Forties was fundamentally flawed. The ‘Super’, as the early hydrogen bomb was known, would have blown itself apart before any appreciable thermonuclear processes were initiated.

Edward Teller and Stanislaw Ulam, émigré scientists from Hungary and Poland respectively, who were working at Los Alamos, found an ingenious solution in 1951. As part of his work on improved fission weapons Ulam had suggested a two-stage fission design. Teller seized on this idea and proposed a first fission stage which would set off a separate fusion stage by means of X-rays transmitted from the fission explosion. Since X-rays are a form of electromagnetic radiation they travel at the speed of light and thus can in principle implode and ignite the thermonuclear fuel before the shock wave from the primary stage blows it apart. This process is known as radiation implosion; and according to normal US nomenclature, a ‘hydrogen’ or ‘thermonuclear’ bomb refers to a weapon which incorporates the Ulam-Teller concept of two (or more) stages and radiation implosion. A prototype H-bomb, ‘Mike’, incorporating these principles was first successfully tested in November 1952 and was followed by the Castle series at Bikini between March and May 1954 in which several thermonuclear weapons with yields larger than one megaton were tested.

In August 1953 the Soviet Union exploded a large nuclear weapon, known in the West as Joe-4, which it announced was thermonuclear. US weapon scientists have known for some time, however, that the yield of Joe-4 was only about 200-300 kilotons and that it was therefore unlikely to have been a hydrogen bomb in the Ulam-Teller sense. This has recently been confirmed by Soviet physicists writing about Sakharov’s role in the project. Joe-4 was a ‘layer-cake’ device with layers of light and heavy elements. The light elements were in the form of the thermonuclear fuel lithium-6-deuteride and the heavy elements were plutonium, uranium-235 and uranium-238. The latter isotope is then fissioned by fast neutrons from the thermonuclear reaction. By far the greater part of the energy of Joe-4 still came from fission, not fusion, so we will follow US terminology by referring to such weapons as thermonuclear-boosted fission weapons rather than thermonuclear weapons or H-bombs. Such boosted fission weapons are not as efficient as two-stage radiation implosion H-bombs and would not be expected to have yields as large as one megaton.

The British decision to build a hydrogen bomb was taken by a sub-committee of the Churchill Cabinet in 1954, in the aftermath of the US Castle test series. The power of those weapons – one reached 15 megatons – seems to have come as a surprise to everyone including the weapon designers, and the British Government decided that they were too dangerous a capability to be left to the US alone. Churchill felt ‘that we could not expect to maintain our influence as a world power unless we possessed the most up-to-date nuclear weapons,’ while the Chiefs of Staff emphasised the need to have as much influence as possible over the use of the H-bomb. So the aims of British thermonuclear policy were political rather than military right from the start: prestige and a US-UK special nuclear relationship were the objectives.

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Letters

Norman Dombey and Eric Grove are wrong to argue (LRB, 22 October) that the US-UK nuclear special relationship prevents ‘a common European nuclear defence policy’ being agreed between Britain and France because the United States would not want its nuclear weapons secrets to be shared with France. In fact, the US has already given and gives France considerable help in the scientific and technical development of her nuclear arms. This was revealed in the latest volume of Giscard d’Estaing’s memoirs, Le pouvoir et la vie: I’affrontement, published last year. He describes a visit from Henry Kissinger in 1974, soon after Giscard became President of France. Kissinger wanted to know if Giscard would continue with the ‘special relations’ (nos rélations spéciales dans le domaine nucléaire) but Giscard had no idea what Nixon’s envoy was talking about. Later, his military staff informed him that France regularly sent her nuclear weapons experts to the United States, where a curious game took place. The French would describe the research they were undertaking and the Americans would indicate if it was a blind alley or not. Technically, the US did not breach the McMahon Act and gave only ‘negative information’ to the French, but according to Giscard, the American-Franco nuclear co-operation, which had ‘gone on for several years’, was invaluable in the successful development of French nuclear weapons. Naturally, all was conducted with the utmost secrecy and Kissinger and President Ford stressed repeatedly the need to keep the contacts utterly secret. At the moment of his successor’s investiture in 1981, Giscard says he informed Mitterrand about the US-France contacts. Mitterrand’s ‘long face nodded and he said nothing,’ writes Giscard.

Giscard’s memoirs are not backed up with any source references but it seems unlikely that he would have invented all of this in such detail. But if it is true, it does make a nonsense of the view that the Americans exclusively favoured the British in the development of nuclear arms and of the view advanced by Dombey and Grove that de Gaulle kept Britain out of the EEC chiefly because of UK military dependency on the US. De Gaulle’s views were more to do with the belief that Britain would not fully join in or accept the responsibility of the political and economic partnership implicit in the EEC. Looking at the Tories’ Maastricht convulsions, from Major’s original opt-outs to present absurdities, who is to say de Gaulle was wrong? Giscard’s account also suggests that the McMahon Act is no obstacle to joint Anglo-French nuclear arms projects in the context of a common European defence programme, should that emerge.

Finally, Giscard underlines the point about nuclear weapons that represents their biggest intellectual challenge. While President, he asked for an exercise to be simulated in which he would have to take a decision on whether or not to authorise their use. The French Army obliged with a realistic enactment involving Soviet thrusts causing massive French losses, and the commanders considered using nuclear missiles to halt the advance. Giscard writes that he would never authorise first use, but would be prepared to secure vengeance if France were attacked with nuclear weapons. Thus the nuclear dilemma. Weapons that cannot be used but dare not be left in the hands exclusively of other powers. Now that all nuclear weapons states are committed to the free market and to the economics of capitalism it should – shouldn’t it – be a lot easier to agree to get rid of them all.

Denis MacShane
Divonne, France

Britain’s thermonuclear bluff continues to this day. The first Trident submarine HMS Vanguard was on its way from Barrow to Faslane when you published this important article. Rational people may fail to understand why we are persisting with the expenditure of £33 billion on this system when the Cold War is over. The UK Government is still as mesmerised as Macmillan was by the status that having the bomb seemingly confers. How can they convincingly argue against nuclear proliferation when they are acting as the ultimate role model for aspiring nuclear nations? Scientific reports have shown that the design of the Trident warhead is fundamentally flawed and dangerous yet they will be regularly transported up and down our motorways with the attendant risk of a catastrophic accident. It is time for public opinion to call the Government’s bluff and demand that the madness of Trident be stopped.

We are glad that Denis MacShane (Letters, 19 November) has raised the question of US policy with respect to nuclear co-operation between Britain and France. It is true that the US has provided France with informal help on her nuclear programme, but as MacShane points out, this help did not breach US Atomic Energy legislation. After over thirty years of US-UK collaboration any exchange of nuclear weapon design information between Britain and France would almost certainly breach that legislation as well as the US-UK agreement on nuclear collaboration for military purposes, unless the appropriate US authorities were to agree to the exchange. And that cannot be taken for granted. In fact Mr Heath was initially keen on nuclear collaboration with France during the negotiations of 1970-72 which led to British accession to the European Community. But Lord Carrington, then Secretary of Defence, persuaded him that there was no point in pursuing the matter because of ‘Britain’s difficulties of disclosing nuclear information received from the Americans’.

The problems of Anglo-French collaboration on nuclear weapon design and manufacture have been reviewed by Andrew Pierre in Nuclear Politics and more fully by Ian Smart in his Adelphi Paper of 1973. The main problem is that even where the warhead is said to be of British design – the warhead used in the Polaris Chevaline system, for example – it is almost impossible to establish that no design information originated in the US. If Britain wished to build a new warhead with the French based on that design for a new standoff missile, the US would be bound to point out to Britain that the design incorporated information of US origin.

A little-known precedent illustrates the point. In the late Sixties Britain was wanting to collaborate with Germany and Holland in setting up a uranium enrichment plant using centrifuge technology, which had been under development in all three countries. But Britain was planning to use a bearing and other components for the centrifuge which had some resemblance to components developed under its 1955 collaboration agreement with the US on civil nuclear energy. This agreement also contained a restriction on transfer to third parties of US-origin information. In spite of the peaceful purpose of the proposed plant, and the fact that the components proposed were substantially different from the original US designs, the US formally asserted a claim that US-origin information was involved. Lawrence Freedman discusses the incident in Britain and Nuclear Weapons.

In this case Britain successfully resisted the US and the Treaty of Almelo was finally agreed between the three countries in 1970. Britain argued that technology constantly evolves and that it was therefore necessary to have a cut-off in the development process after which any claim of national origin was pointless. While this was accepted by the US or at least not pursued further, we cannot imagine that the US would take a similar line over weapon design information. Indeed the ultimate penalty for transferring weapon design information to nationals of other countries without consent is still death under US law and the US has never worried overmuch about the extra-territorial applicability of its laws, as General Noriega would testify. So it is unlikely that Britain or indeed individual British officials would be prepared to reveal weapon design information to French nationals without US consent, and that consent would be difficult to obtain. It is possible, however, for Britain and France to collaborate on operational matters such as the targeting and deployment of nuclear weapons, or on the joint manufacture of a missile or other weapon delivery system, without asking the US for permission.

We should like to lake this opportunity to thank all those who corresponded with us about the article (LRB, 22 October). As a result we are able to fill in some gaps in the original version. We now have better evidence that Orange Herald, which was tested in front of journalists, was the large fission ‘fallback’. Lorna Arnold, in her official history of British tests in Australia, A Very Special Relationship, writes that after the Grapple series Britain had ‘an extremely expensive high-yield warhead for a ballistic missile’. ‘Extremely expensive’ indicates the ‘fallback’ which was ‘expensive in fissile material’, according to Cook’s biographers. The ballistic missile is Blue Streak and Morton’s official Australian history of Woomera, Fire across the Desert, identifies the Orange Herald test as the test of the Blue Streak warhead. We now estimate that this weapon would have had a yield of 300-500 kilotons. The fallback never went into production on account of the cancellation of Blue Streak.

We were not quite right about Yellow Sun Mark: I, the high-yield fission weapon which went into service in 1958. This was not the Orange Herald fallback, as it would have been too expensive. It must, therefore, have been a large Red Beard of around 100-200 kilotons. The smaller versions of Red Beard were tested in the Antler series at Maralinga in Australia in September and October 1957 and the high-yield version was tested as Grapple X at Christmas Island in November 1957: it was too risky politically to test such a large weapon in Australia.